Solvothermal Preparation of Nano-Sized CaWO4 Particles

2007 ◽  
Vol 124-126 ◽  
pp. 1265-1268 ◽  
Author(s):  
Sulawan Kaowphong ◽  
Titipun Thongtem ◽  
Somchai Thongtem
Keyword(s):  
Pure Water ◽  
Solvothermal Reaction ◽  
Hrtem Image ◽  
Scheelite Structure ◽  
Glycerol Water ◽  
Calcium Salts ◽  
Solvothermal Preparation

CaWO4 was prepared by solvothermal reaction of Na2WO4.2H2O and calcium salts (CaCl2.2H2O, Ca(NO3)2.4H2O and Ca(CH3COO)2) in solvent containing a variety of glycerol/water ratios at 160 oC for 6 h. By using XRD, SEM, TEM and ED, the products compose of nano-sized CaWO4 particles with scheelite structure but different morphologies. Interplanar spaces between (101) planes were determined from HRTEM image, ED patterns and XRD spectra are 0.424, 0.474 and 0.476 nm, respectively. Luminescent intensities of the products prepared in pure water are the highest and their central peaks are the same at 444 nm. In addition, Ca, W and O were detected using EDX.

Luminescence of MWO4 (M =Ca, Sr, Ba and Pb) Prepared by Solvothermal Reaction

2007 ◽  
Vol 124-126 ◽  
pp. 315-318 ◽  
Author(s):  
Titipun Thongtem ◽  
Sulawan Kaowphong ◽  
Somchai Thongtem
Keyword(s):  
Propylene Glycol ◽  
Single Phase ◽  
Sodium Tungstate ◽  
Solvothermal Reaction ◽  
Scheelite Structure ◽  
Glycerol Water ◽  
Luminescent Spectra

MWO4 (M = Ca, Sr, Ba and Pb) was solvothermally prepared using metallic nitrates and sodium tungstate in 25/5 volume ratios of glycerol/water (SGL) and propylene glycol/water (SPG) at 160 oC for 6 h. XRD revealed the presence of MWO4 single phase with tetragonal scheelite structure. The strong W-O stretching band of WO4 tetrahedrons was detected at 705-875 cm-1. The product images show nano-sized particles in basic SGL and SPG solvents and flower-like particles in SPG solvent with pH of 6.7. Central peaks of the luminescent spectra are 445, 446, 443 and 440 nm, respectively.

scholarly journals The Function of the Anal Gills of the Mosquito Larva

1933 ◽  
Vol 10 (1) ◽  
pp. 16-26 ◽  
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
Carbon Dioxide ◽  
Body Surface ◽  
Mosquito Larva ◽  
Anterior Part ◽  
Pure Water ◽  
Posterior Part ◽  
The Body ◽  
Glycerol Water ◽  
Hypertonic Solutions ◽  
Spontaneous Aggregation

The anal gills of the mosquito larva (Aedes argenteus) are the only region of the body that is freely permeable to water. In hypertonic solutions of sugar or glycerol, water is extracted from the gills and the larva shrinks. In pure water this is absorbed by the gills and later excreted by the Malpighian tubes. The absorption of water appears to be effected mainly by osmosis. Larvae can mature without the gills, but they seem to grow more slowly, and show almost no parenteral absorption of water. Normally the larva swallows very little fluid. The fluid in the gut is probably secreted in the posterior part of the mid-gut and reabsorbed in the anterior part and in the caeca. Some of the water excreted by the Malpighian tubes is reabsorbed in the rectum. As judged by the spontaneous aggregation of the flagellate Polytoma, oxygen is absorbed by submerged larvae all over the body surface, but most actively at the base of the gills. Carbon dioxide is given off equally all over the body surface. It is concluded that the anal gills are primarily water-absorbing organs, and are only incidentally concerned in respiration.

Interactions of Glycerol, Diglycerol, and Water Studied Using Attenuated Total Reflection Infrared Spectroscopy

2020 ◽  
Vol 74 (7) ◽  
pp. 767-779 ◽  
Author(s):  
Akari Habuka ◽  
Takeshi Yamada ◽  
Satoru Nakashima
Keyword(s):  
Infrared Spectroscopy ◽  
Pure Water ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Outer Side ◽  
Water Molecules ◽  
Glycerol Water ◽  
Oh Groups ◽  
Water Solutions ◽  
Band Area

In order to examine the mixing properties of glycerol–water and diglycerol–water solutions, these solutions were measured using attenuated total reflection infrared spectroscopy. The absorbance spectra corrected for 1 µm thickness were subtracted by pure polyols for obtaining water spectra, and by pure water for polyol spectra. Both asymmetric and symmetric CH2 stretching vibration bands (around 2940, 2885 cm−1) shifted about 10 cm−1 to lower wavenumber side (redshifts) with increasing polyol concentrations, especially at higher concentrations. Redshifts of C–O–H rocking bands (around 1335 cm−1) with increasing polyol concentrations are slightly larger for diglycerol–water (10 > 6 cm−1) than glycerol–water solutions. C–O stretching bands of CHOH groups (1125 and 1112 cm−1) shift slightly but in opposite sides for glycerol and diglycerol at highest polyol concentrations (90–100 wt%). These shifts of CH2 stretching, COH rocking, and CO stretching of CHOH at higher polyol concentrations suggest interactions of outer CH2 with inner CHOH groups of surrounding polyols. The normalized band area changes with polyol concentrations could be fitted by quadratic polynomials possibly due to mixtures of different interactions between water–water, polyol–water, and polyol–polyol molecules. The OH stretching band for diglycerol 90 wt% shows three humps indicating at least three OH components: long, medium, and short H bond water molecules. Short H bond water molecules are the major component possibly between inner CHOH and outer side CH2OH groups, while the long H component might loosely bind to outer CH2OH groups.

Thermal Conductivities of Porous Rocks Filled with Stagnant Fluid

1961 ◽  
Vol 1 (01) ◽  
pp. 37-42 ◽  
Author(s):  
D. Kunii ◽  
J.M. Smith
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Water Solution ◽  
Pure Water ◽  
General System ◽  
Practical Significance ◽  
Glycerol Water ◽  
Starting Point ◽  
Thermal Conductivities ◽  
Stagnant Fluid

Abstract Effective thermal conductivities of sandstones filled with stagnant fluids were measured using a steady-state technique. Data were obtained for seven sandstone samples, taken from four different locations and ranging in permeability from 18 to 590 md. The measurements with gases (helium, nitrogen, air and carbon dioxide) covered a pressure range from 0.039 psia to 400 psig. Data were taken for four liquids - n-heptane, methyl alcohol, 79.8 weight per cent glycerol-water solution and pure water at atmospheric pressure. The experimental results were used to evaluate the theoretical equations for predicting stagnant conductivities developed earlier. The low-pressure measurements permitted evaluation of the consolidation parameter hpDp/ks (necessary to utilize the theory) for the various types of sandstones. Using these characteristic values, the theoretical equations correlated well with the experimental conductivity data for the several fluids and rock samples. Introduction An aspect of heat transfer in solid-fluid systems of considerable current interest is the effective thermal conductivity of porous media. The stimulus for study of the subject arises from the need for sound procedures for designing thermal methods of petroleum production. The general system occurs when there exists a flow of fluid through the pores of the solid material. However, a logical starting point in developing a theory for predicting the effective thermal conductivity in the general system is to attack the special case when the porous solid is filled with stagnant fluid. Since the flow rates anticipated in thermal production processes are very low, such stagnant conductivities k are also of practical significance.

Post-Processing and Properties of Polyethersulfone Hollow Fiber Membrane

2012 ◽  
Vol 476-478 ◽  
pp. 2389-2392
Author(s):  
Ping Lan ◽  
Wei Wang ◽  
Jian Da Cao
Keyword(s):  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Pure Water ◽  
Water Flux ◽  
Hot Water ◽  
Hollow Fiber Membranes ◽  
Post Processing ◽  
Glycerol Water ◽  
Fiber Membranes ◽  
Pure Water Flux

Polyethersulfone (PES) hollow fiber membranes have been widely used in many fields, such as ultrafiltration, microfiltration, reverse osmosis, liquid/liquid or liquid/solid separation, gas separation, hemodialysis, and so on. In this paper, the sheet PES hollow fiber membranes were prepared and post-processing of membranes were studied. Suction method and pressing hot water method can both increase pure water flux of membrane. Suction method is more efficient and with a smaller time to increase pure water flux. After membrane was soaked into glycerol/water solution, pure water flux of membrane increased greatly and the length shrinkage ratio of the membrane was more smaller.

scholarly journals Design and Fabrication of a Microfluidic Viscometer Based on Electrofluidic Circuits

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 375 ◽  
Author(s):  
Bo-Bi Tzeng ◽  
Yung-Shin Sun
Keyword(s):  
Pressure Drop ◽  
Pure Water ◽  
Sample Pretreatment ◽  
Pdms Membrane ◽  
Hydraulic Pressure ◽  
Pdms Layer ◽  
Glycerol Water ◽  
Voltage Difference ◽  
Measured Voltage ◽  
Liquid Samples

This paper reports a microfluidic viscometer based on electrofluidic circuits for measuring viscosities of liquid samples. The developed micro-device consists of a polydimethylsiloxane (PDMS) layer for electrofluidic circuits, a thin PDMS membrane, another PDMS layer for sample pretreatment, and a glass substrate. As the sample flows inside the microfluidic channel, its viscosity causes flow resistance and a pressure drop along this channel. This pressure drop, in turn, generates a hydraulic pressure which deforms the PDMS membrane, causing changes in the cross-sectional area and the electrical resistance of the electrofluidic resistor. This small resistance change is then measured via the electrofluidic Wheatstone bridge to relate the measured voltage difference to the fluidic viscosity. The performance of this viscometer was first tested by flowing nitrogen gas with controllable pressures into the device. The relationship between measured voltage difference and input gas pressure was analyzed to be linear in the pressure range of 0–15 psi. Another test using pure water indicated good linearity between measured voltage difference and flow rate in the rate range of 20–100 μL/min. Viscosities of glycerol/water solutions with volume/volume (v/v) concentrations ranging from 0 to 30% were measured, and these values were close to those obtained using commercially available viscometers. In addition, the sample-pretreatment layer can be used to mix and/or dilute liquid samples to desired concentrations. Therefore, this microfluidic device has potential for measurements of fluidic viscosity in a fast, accurate, and high-throughput manner.

Actuation of a magnetically coated swimmer in viscous media with a magnetic particle imaging scanner

2020 ◽  
Vol 6 (3) ◽  
pp. 349-352
Author(s):  
Anna C. Bakenecker ◽  
Carlos Chinchilla ◽  
Thorsten M. Buzug
Keyword(s):  
Magnetic Particle ◽  
Pure Water ◽  
The Body ◽  
Magnetic Actuation ◽  
Glycerol Water ◽  
Mixing Ratios ◽  
Magnetic Particle Imaging ◽  
Viscous Media ◽  
Real Time Tracking ◽  
Particle Imaging

AbstractMagnetic actuation of medical devices is of great interest in improving minimally invasive surgery and enabling targeted drug delivery. With untethered, magnetically coated swimmers it is aimed at reaching regions of the body difficult to access with catheters. Such a swimmer was previously presented, which is suitable for the navigation by the magnetic fields of a magnetic particle imaging (MPI) scanner. The swimmer could be imaged with MPI as well, enabling the tomographic real-time tracking of the actuation process. In this work the steerability of the swimmer is further investigated in media of varying viscosities. For this, glycerol-water-mixtures of different mixing ratios were used. The velocities of the swimmer were measured for viscosities between those of pure glycerol and pure water. The experiments were performed with an MPI scanner at maximal magnetic field strength of the actuating fields. A viscosity range was found in which the swimmer is steerable by the fields of an MPI scanner, which leads to a prediction of the applicability of the swimmer in different body fluids.

scholarly journals Concentration Effects in the Interaction of Monoclonal Antibodies (mAbs) with their Immediate Environment Characterized by EPR Spectroscopy

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2528 ◽  
Author(s):  
Haeri ◽  
Blaffert ◽  
Schöffmann ◽  
Blech ◽  
Hartl ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Epr Spectroscopy ◽  
Network Formation ◽  
Pure Water ◽  
Spin Probes ◽  
High Concentration ◽  
Glycerol Water ◽  
High Concentrations ◽  
Intermolecular Distances ◽  
Very High

Monoclonal antibodies (mAbs) are often needed and applied in high concentration solutions, >100 mg/mL. Due to close intermolecular distances between mAbs at high concentrations (~10-20 nm at 200 mg/mL), intermolecular interactions between mAbs and mAbs and solvent/co-solute molecules become non-negligible. Here, EPR spectroscopy is used to study the high-concentration solutions of mAbs and their effect on co-solvated small molecules, using EPR “spin probing” assay in aqueous and buffered solutions. Such, information regarding the surrounding environments of mAbs at high concentrations were obtained and comparisons between EPR-obtained micro-viscosities (rotational correlation times) and macroscopic viscosities measured by rheology were possible. In comparison with highly viscous systems like glycerol-water mixtures, it was found that up to concentrations of 50 mg/mL, the mAb-spin probe systems have similar trends in their macro- (rheology) and micro-viscosities (EPR), whereas at very high concentrations they deviate strongly. The charged spin probes sense an almost unchanged aqueous solution even at very high concentrations, which in turn indicates the existence of large solvent regions that despite their proximity to large mAbs essentially offer pure water reservoirs for co-solvated charged molecules. In contrast, in buffered solutions, amphiphilic spin probes like TEMPO interact with the mAb network, due to slight charge screening. The application of EPR spectroscopy in the present work has enabled us to observe and discriminate between electrostatic and hydrophobic kinds of interactions and depict the potential underlying mechanisms of network formation at high concentrations of mAbs. These findings could be of importance as well for the development of liquid-liquid phase separations often observed in highly concentrated protein solutions.

Phase Transformation of Nanocrystalline CdS Synthesized by Solvothermal Reaction

2007 ◽  
Vol 544-545 ◽  
pp. 777-780
Author(s):  
Titipun Thongtem ◽  
Anukorn Phuruangrat ◽  
Somchai Thongtem
Keyword(s):  
Phase Transformation ◽  
Pure Water ◽  
Longitudinal Optical ◽  
Ammonia Solution ◽  
Solvothermal Reaction ◽  
Raman Analysis ◽  
Pl Spectra

CdS was synthesized by solvothermal reaction of CdCl2.2.5H2O and (NH2)2CS in ammonia solution at 200 oC for 10 h. XRD, TEM and SAED show that the products are nanocrystalline CdS. The phase is 100 % hexagonal (hcp) in pure water, gradually transformed into cubic with the increase of NH3 concentration, and 100 % cubic in 25 % NH3 solution. By using FTIR, no solvents were detected in the products. Raman analysis revealed the presence of 1LO (longitudinal optical) and 2LO phonon peaks at 297.0 and 597.1 cm-1 for CdS (hcp), and 295.9 and 596.9 cm-1 for CdS (cubic), respectively. Strong peaks of the photoluminescent (PL) spectra were detected at 450 nm for hcp, and 519 nm for cubic.

Facile Solvothermal Preparation and Tribological Performance of PbSe Nanoparticles

2019 ◽  
Vol 11 (1) ◽  
pp. 34-39
Author(s):  
Feng Yang ◽  
M.Q. Xue
Keyword(s):  
Tribological Properties ◽  
Functional Materials ◽  
Surface Friction ◽  
Lubricant Additive ◽  
Solvothermal Reaction ◽  
Xrd Pattern ◽  
Base Oil ◽  
Metal Dichalcogenides ◽  
Solvothermal Preparation ◽  
Important Branch

Background: Metal dichalcogenides are important branch of functional materials, which have renewed great attention in academia and industry because of their various significant applications. Objective: The aim of the present study is to synthesize PbSe by solvothermal and investigate PbSe’s tribological properties. Results: The XRD pattern of the sample can be readily indexed as PbSe. The tribological properties of PbSe as additives in base oil were investigated using a UMT-2 ball-on-disc tribotester. Under the determinate conditions, the friction coefficient of the base oil containing 1.0 wt. % PbSe was lower than that of the base oil. A stable tribofilm on the rubbing surface could explain the improved tribological properties of PbSe as additives. Conclusion: PbSe nanoparticles have been synthesized successfully via solvothermal reaction. The preliminary tribological experimental results show that the PbSe could be a lubricant additive to the base oil and able to improve the tribological properties under the optimal concentration (1.0 wt. %). The result of tribological experiments demonstrated that the stable tribofilm with PbSe nanoparticles on the rubbing surface could benefit to decreasing surface friction.

Sign in / Sign up

Export Citation Format

Share Document